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Biomedical subjects

B E Wexler

Publications and source records attributed to B E Wexler.

At least 19 recordsLinked to original sources
PubMed2005

Cognitive training of verbal memory using a dichotic listening paradigm: impact on symptoms and cognition.

OBJECTIVE: The objective was to investigate the impact of a verbal memory training task on psychiatric symptoms and cognition in schizophrenia. METHOD: As part of a larger, 6-month cognitive remediation program, 57 patients with schizophrenia were randomly assigned to receive performance-based, hierarchical training on a verbal memory task based on a dichotic listening (DL) with distracter paradigm. These patients were compared with 68 patients who had been randomly assigned to a control condition. RESULTS: Training on the DL task was not associated with changes in general psychopathology or auditory hallucinations (AH) specifically. Training was associated with improvements in verbal memory, but not attention. CONCLUSION: The current investigation adds to the growing literature on the effectiveness of cognitive remediation training and indicates that training on the DL task enhances verbal episodic memory. The results do not support the use of DL training as a method for reducing AH.

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PubMed2003

Cognitive remediation of working memory deficits: durability of training effects in severely impaired and less severely impaired schizophrenia.

OBJECTIVE: To determine whether augmenting work therapy (WT) with neurocognitive enhancement therapy (NET) yields greater improvement in working memory performance than WT alone and whether there is an interaction with severity of impairment. METHOD: A total of 102 participants with schizophrenia or schizoaffective disorder were categorized as severely or less severely cognitively impaired and randomly assigned to receive NET + WT or WT alone. NET consisted of cognitive training exercises in attention, memory, executive function, and social information processing, and WT was a 6-month work program. RESULTS: Comparison on Digits Backwards from intake to follow-up revealed significantly greater improvement for participants receiving NET + WT, but there was no interaction with severity group. Follow-up 6 months after training showed that training effects endured. CONCLUSION: NET + WT improved working memory for most participants regardless of impairment severity. Intensity and duration of training may have contributed to duration of effects. Findings support continued exploration of cognitive remediation.

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PubMed2001

Neurocognitive enhancement therapy with work therapy: effects on neuropsychological test performance.

BACKGROUND: Cognitive deficits are a major determinant of social and occupational dysfunction in schizophrenia. In this study, we determined whether neurocognitive enhancement therapy (NET) in combination with work therapy (WT) would improve performance on neuropsychological tests related to but different from the training tasks. METHODS: Sixty-five patients with schizophrenia or schizoaffective disorder were randomly assigned to NET plus WT or WT alone. Neurocognitive enhancement therapy included computer-based training on attention, memory, and executive function tasks; an information processing group; and feedback on cognitive performance in the workplace. Work therapy included paid work activity in job placements at the medical center (eg, mail room, grounds, library) with accompanying supports. Neuropsychological testing was performed at intake and 5 months later. RESULTS: Prior to enrollment, both groups did poorly on neuropsychological testing. Patients receiving NET + WT showed greater improvements on pretest-posttest variables of executive function, working memory, and affect recognition. As many as 60% in the NET + WT group improved on some measures and were 4 to 5 times more likely to show large effect-size improvements. The number of patients with normal working memory performance increased significantly with NET + WT, from 45% to 77%, compared with a decrease from 56% to 45% for those receiving WT. CONCLUSIONS: Computer training for cognitive dysfunction in patients with schizophrenia can have benefits that generalize to independent outcome measures. Efficacy may result from a synergy between NET, which encourages mental activity, and WT, which allows a natural context for mental activity to be exercised, generalized, and reinforced.

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PubMed2001

Functional magnetic resonance imaging of cocaine craving.

OBJECTIVE: Identification of brain activity associated with craving is important for understanding the neurobiology of addiction. METHOD: Brain activity was measured in cocaine addicts and healthy subjects by functional magnetic resonance imaging (fMRI) while the subjects watched videotapes designed to elicit happy feelings, sad feelings, or the desire to use cocaine. The subjects indicated the onset of drug craving or emotional response, allowing comparison of groups before and after such feelings. RESULTS: Robust activation of the anterior cingulate was evident in patients watching cocaine-cue tapes but not in patients watching happy or sad tapes or in healthy subjects under any condition. Anterior cingulate activation preceded the reported onset of craving and was evident in patients who did not report craving. In contrast, patients showed less activation than healthy subjects during the cocaine-cue tapes in areas of the frontal lobes. After the reported onset of craving, cocaine-dependent subjects showed greater activity than healthy subjects in regions that are more active in healthy subjects when they watch sad tapes than when they watch happy tapes, suggesting a physiologic link between cocaine-cue responses and normal dysphoric states. Dynamic aspects of regional brain activations, but not the location of activations, were abnormal in cocaine-dependent subjects watching sad tapes, suggesting more general affective dysregulation. Patients showed low activation of sensory areas during initial viewing of all videotapes, suggesting generalized alteration in neuroresponsiveness. CONCLUSIONS: Cocaine cues lead to abnormally high cingulate and low frontal lobe activation in cocaine addicts. Addicts also show more general abnormalities in affect-related brain activation.

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PubMed2001

Functional MR imaging of regional brain activation associated with the affective experience of pain.

OBJECTIVE: Current models propose that the experience of pain includes both sensory and affective components. Our purpose was to use functional MR imaging to determine areas of the brain engaged by the affective dimension of pain. SUBJECTS AND METHODS: Twelve healthy adults underwent functional MR imaging using a gradient-echo echoplanar technique while a cold pressor test, consisting of cold and pain tasks, was applied first to one foot and then to the other. The cold task involved the application of cold water (14-20 degrees C) that was not at a painful level. For the pain task, the water temperature was then lowered to a painful temperature (8-14 degrees C) and subsequently to the pain threshold (3-8 degrees C). Images acquired at room temperature before the cold and pain tasks served as a baseline task. Composite maps of brain activation were generated by comparing the baseline task with the cold task and the cold task with the pain task. The significance of signal changes was estimated by randomization of individual activation maps. RESULTS: Cold-related activation (p < 0.01) was found in the postcentral gyrus bilaterally, laterally, and inferiorly to the primary motor-sensory area of the foot and at a site near the second somatosensory site. Activation also occurred in the frontal lobe (the bilateral middle frontal gyri and the right inferior frontal gyrus), the left anterior insula, the left thalamus, and the superior aspect of the anterior cingulate gyrus (seen at one slice location). Pain-related activation (p < 0.01) included the anterior cingulate gyrus (seen at four slice locations); the superior frontal gyrus, especially on the right; and the right cuneus. CONCLUSION: Compared with the basic sensory processing of pain, the affective dimension of pain activates a cortical network that includes the right superior frontal gyrus, the right cuneus, and a large area of the anterior cingulate gyrus.

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PubMed2000

Preliminary evidence of improved verbal working memory performance and normalization of task-related frontal lobe activation in schizophrenia following cognitive exercises.

OBJECTIVE: The authors' goal was to evaluate the possibility of treating brain and behavioral aspects of verbal memory dysfunction in patients with schizophrenia through cognitive exercises. METHOD: Eight patients did daily verbal memory exercises that became progressively more difficult over a 10-week training period. Memory performance and regional brain activations during a verbal memory task were assessed before and after these exercises. RESULTS: Verbal but not nonverbal memory performance improved after training; three patients made substantial gains, and five showed little change. Performance gains were correlated with increases in task-related activation of the left inferior frontal cortex. One patient given 5 extra weeks of training 6 weeks after the initial training period showed maintenance of initial performance gains 6 weeks after training, further improvement after the second period of training, and normalization of task-related activation of the left inferior frontal cortex. CONCLUSIONS: Verbal memory deficits can be ameliorated by memory exercises in some patients with schizophrenia. Performance improvements are associated with increased task-related activation of the same brain region that is activated during verbal memory tasks in healthy individuals.

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PubMed2000

Verbal processing deficits in schizophrenia.

The authors reported that a subgroup of schizophrenic patients performed well on a tone serial position task but was impaired on an auditory word serial position task (Wexler, Stevens, Bowers, Cerniak, & Goldman-Rakic, 1998). This study assessed 30 schizophrenic and 32 controls (matched for comparable tone discrimination) on 4 versions of the verbal serial position tasks and 2 tone serial position tasks. Patients performed poorly on all verbal tasks but performed comparably to controls when tones served as stimuli. Proactive interference and visual presentation further compounded the verbal deficits. Deficits persisted with pronounceable nonword stimuli. These findings provide evidence of specific deficits in language-related processing, although the authors could not rule out the possibility that the differential effects that were observed between the tone and word tasks, and particularly among the verbal tasks, may result from differing discriminating power of the different tests.

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PubMed1999

California Verbal Learning Test practice effects in a schizophrenia sample.

Practice effects on the California Verbal Learning Test (CVLT; >Delis et al., 1987), a measure of new learning and memory, were evaluated in a sample of patients with schizophrenia who were administered the CVLT at baseline, week 10, and week 14 in the context of a study of the effects of a non-pharmacological intervention on psychiatric status. Large effects attributable to prior exposure to the test were evident at weeks 10 and 14. These effects indicate that caution must be exercised in interpreting serial performances on this commonly used test, whether in research or clinical circumstances. Additionally, although the exact nature of the learning involved is unclear, the influence of prior exposure on later performance reveals considerable retention over time of new information in this sample of persons with schizophrenia.

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PubMed1999

Perceptual asymmetry differences between major depression with or without a comorbid anxiety disorder: a dichotic listening study.

Predictions that anxious and nonanxious depression would differ in perceptual asymmetry (PA), as well as in sensitivity for perceiving emotional words, were evaluated using dichotic listening tasks. A total of 149 patients having a major depressive disorder (51 with and 98 without an anxiety disorder) and 57 healthy controls were tested on fused-word and complex tone tasks. The anxious and nonanxious depression groups showed a consistent difference in PA across tasks; that is, the anxious group had a larger left-ear advantage for tones and a smaller right-ear advantage for words when compared with the nonanxious group. There was no group difference in sensitivity for perceiving emotional words. Patients having an anxious depression appear to have a greater propensity to activate right than left-hemisphere regions during auditory tasks, whereas those having a nonanxious depression have the opposite hemispheric asymmetry.

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PubMed1999

Physics and the quandaries of contemporary psychiatry: review and research.

Although in physics, quantum mechanical principles have long replaced Newtonian ones, we continue to apply the latter in models of the mind and its diseases. This article discusses the possible theoretical application of quantum principles to mind-brain function. Empirically, this study tested which of these principles practicing psychiatrists found more applicable in clinical practice. Psychiatrists (N = 382) at universities around the United States were asked to answer a questionnaire that contained clinical scenarios reflecting mental, interpersonal, or therapeutic processes corresponding to quantum or classical physical principles. Respondents (N = 191) were significantly more likely to rate scenarios reflecting quantum principles as being consistent with their experience than they were those reflecting classical principles (p < .0005). This effect was significantly greater in more experienced psychiatrists. Quantum physics, a powerful tool in understanding properties of both micro- and macro-level phenomena, may have implications at the human level, invoking the roles of observer, interpersonal relationships, and resources such as resiliency and creativity.

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PubMed1998

Word and tone working memory deficits in schizophrenia.

BACKGROUND: Verbal memory deficits have been reported in many studies of patients with schizophrenia. We evaluated the specificity of these deficits by comparing patients and control subjects on several verbal and nonverbal auditory memory tests. METHODS: Performance of stable, medicated outpatients with DSM-III-R diagnoses of schizophrenia (N = 38) was compared with that of healthy subjects (N = 39) on a word list immediate recall task, tone delayed discrimination tasks, and word and tone serial position tasks. Before memory testing, patients were divided into 2 groups based on their ability to perform normally on a screening test requiring pitch discrimination and sustained attention. RESULTS: The nonverbal tests were more difficult for control subjects than the verbal tests. Despite this, patients who performed normally on the screening test of perception and attention performed normally on both nonverbal tests but had highly significant deficits on both verbal tests (P<.001 and P = .02). Patients who performed poorly on the screening test had highly significant performance deficits on all the memory tests. CONCLUSIONS: One subgroup of patients with schizophrenia has a selective deficit in verbal memory despite normal motivation, attention, and general perceptual function. Another group has deficits in multiple aspects of cognitive function suggestive of failure in early stages of information processing.

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PubMed1998

Cortical dysfunction in schizophrenia during auditory word and tone working memory demonstrated by functional magnetic resonance imaging.

BACKGROUND: Verbal learning and memory deficits are among the most severe cognitive deficits observed in schizophrenia. We have demonstrated that such deficits do not extend to working memory for tones in a substantial number of patients even when verbal working memory is impaired. In this study we used functional magnetic resonance imaging to study the neural basis of this dissociation of auditory verbal and nonverbal working memory in individuals with schizophrenia. METHODS: While undergoing functional magnetic resonance imaging, 12 schizophrenic patients and 12 matched control subjects performed auditory Word Serial Position Task and Tone Serial Position Task. RESULTS: Both tasks produced activation in frontal cortex and temporal and parietal lobes of the cerebrum in both groups. While robust activation was observed in the left inferior frontal gyrus (areas 6, 44, and 45) in the control group during the Word Serial Position Task, activation in the patient group was much reduced in these areas and failed to show the same task-specific activation as in controls. Reduced activation in patients was not confined to the inferior frontal gyrus, but also extended to a medial area during the Tone Serial Position Task and to premotor and anterior temporal lobe areas during both tasks. CONCLUSIONS: These findings support the hypothesis that abnormalities in cortical hemodynamic response in the inferior frontal gyrus underlie the verbal working memory deficit in schizophrenia. The relationship of verbal working memory deficits to other cognitive functions suggests that abnormal functioning in the speech-related areas may reflect a critical substrate of a broad range of cognitive dysfunctions associated with schizophrenia.

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PubMed1998

Functional MR imaging of regional brain responses to pleasant and unpleasant odors.

BACKGROUND AND PURPOSE: Odors can elicit a range of behaviors and emotions. Our purpose was to identify regional activation of the human cerebral cortex in response to pleasant (positive hedonic value) and unpleasant (negative hedonic value) odors. METHODS: Thirteen neurologically normal adults underwent functional MR imaging of frontal and anterior temporal brain regions with a gradient-echo echo-planar technique. Eleven candidate regions of interest (ROIs) were identified on the first half of the data set based on t-map comparisons of signal intensities during administration of clementine (pleasant odor), isovaleric acid (unpleasant odor), and clear air (control odor). These ROIs were applied to the second half of the data set, and the number of voxels activated with the odorants was compared with the number of voxels activated during clear air trials, using independent t-tests. RESULTS: Clementine activated five cortical areas: Brodmann's area (BA) 8, BA 32 (lateralized to left), BA 46/9, BA 6 (lateralized to right), and the insula. Isovaleric acid activated four of the five regions without lateralization; no BA 8 activity was seen. Clementine produced more activity than isovaleric acid in the left insula, and isovaleric acid produced more activity than clementine in the left BA 6. No activation was detected in the orbitofrontal cortex or in the medial temporal lobes. Subjects rated clementine, isovaleric acid, and clear air as being pleasant, unpleasant, and neutral, respectively. CONCLUSION: Activation in frontal regions may represent brain processes linked to olfactory networks. There may be regional specialization based on odorant hedonic values.

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PubMed1997

Normal neurocognitive performance after extended practice in patients with schizophrenia.

This study evaluated new methods for improving the performance of patients with schizophrenia on specific neurocognitive tasks. Patients (n = 22) practiced sustained perceptual, memory and motor tasks 5 times/week for 10 weeks. Tasks were initially easy enough for patients to do well, but were made gradually more difficult over the 10 weeks. Patients received base pay and performance-based monetary supplements. No coaching or ongoing instruction was provided, and performance gains were assumed to depend upon implicit learning. High functioning healthy controls (n = 5) were given the same tasks at difficulty levels comparable to those achieved by patients after 10 weeks of practice. After 10 weeks of practice, 16 of the 22 patients performed as well or better than the best control on the perceptual and memory tasks, and 11 patients performed within the range of control subjects on the motor task. Half of the patients retested 6 months after training maintained supranormal performance, while the others showed marked performance declines. Patients with schizophrenia appear to have greater potential for neurocognitive improvement, and potentially for employment, than generally appreciated.

Adult↗
PubMed1997

An fMRI study of the human cortical motor system response to increasing functional demands.

Functional magnetic resonance imaging (fMRI) was used to study activation changes in the human primary motor-sensory areas (MAs), supplementary motor areas (SMAs), premotor areas (PMAs) and the superior and inferior parietal areas (SPAs, IPAs) during right hand finger movements as the rate, force and complexity of movement were varied. A preliminary reproducibility study of a single subject doing the same repetitive index finger movements in nine different sessions over a six week period demonstrated highly consistent and highly localized activation in the contralateral MA. ANOVAs demonstrated highly significant main effects of increasing the force and complexity of movement, thereby illustrating the distributed and integrated systemic character of the cortical motor system. Interactions between brain region and the rate and complexity of movements suggested functional specialization of some components of the system. Increasing the rate of movement led to increased activity only in the contralateral MA; increasing complexity led to greater increases in activity in the left and right SPAs and the left IPA than in other areas. Although activation was evident in varying degree throughout the multiple motor areas, only the MAs showed consistent lateralization of activation.

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PubMed1997

Functional magnetic resonance imaging assessment of the human brain auditory cortex response to increasing word presentation rates.

In an investigation of the auditory cortex response to speech, six subjects were studied using echo-planar functional magnetic resonance imaging (fMRI) at 2.1T. The subjects were asked to listen to English nouns presented at various rates ranging from 0 words per minute (wpm) to 130 wpm while fMRI images encompassing their primary and posterior superior secondary auditory cortices were acquired. An asymmetric spin echo imaging sequence was used with an induced T2 weighting of 50 ms to allow for transverse relaxation effects. Images were acquired in two or four axial-oblique slices with a repetition time of 3.75 or 7.5 s, in plane resolution of 6 x 3 mm, and a slice thickness of 5 mm. Localized activation centered over grey matter was consistently observed in all subjects in the transverse temporal gyrus (TTG), the transverse temporal sulcus (TTS), and the posterior superior aspect of the superior temporal gyrus (STG). The total activate volume and the integrated signal response in bilateral primary and posterior superior secondary auditory cortices increased with increasing rate of word presentation, peaking at 90 wpm (with some intersubject variability) with a subsequent fall at 130 wpm. There were no significant differences in the rate dependence of the signal response in bilateral primary and bilateral posterior superior secondary auditory cortices (P < 0.05).

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PubMed1996

Affective reactivity of cognitive functioning and family history in schizophrenia.

This article reports the results of two related studies investigating the association between affective reactivity of cognitive functioning in schizophrenia and family psychiatric history. In Study #1, we examined affective reactivity of positive formal thought disorder symptoms in 29 schizophrenic inpatients. We found that thought disorder was greatly exacerbated by negative affect in those patients with a family history of schizophrenia (SFH) (n = 11), and not in those without the family history (SNFH) (n = 18). In Study #2, we replicated this finding with a stable outpatient sample (n = 10). We also administered dichotic listening tests using affectively neutral and affectively negative stimuli, and found that right-ear advantage was more markedly diminished on the affectively negative task than on the neutral task in the SFH (n = 6) but not the SNFH (n = 4) subjects. These findings support our hypothesis that cognitive symptoms in schizophrenia are exacerbated by negative affect, and that this affective reactivity of symptoms is associated with a familial form of the disorder.

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